"""
LuCI HTTP Firmware Flasher for OpenWrt devices.

Tự động hoá 3 bước flash qua web interface LuCI:
  1. Login → lấy sysauth cookie + stok token
  2. Upload firmware.bin (multipart)
  3. Confirm (Proceed) → thiết bị flash và reboot

Tương thích:
  - Barrier Breaker 14.07 (field: username/password)
  - OpenWrt mới hơn      (field: luci_username/luci_password)
"""

import re
import time
import os
from typing import Optional

import requests


def _extract_stok(text: str) -> Optional[str]:
    """Tách stok token từ URL hoặc body HTML. Trả về None nếu không tìm thấy."""
    m = re.search(r";stok=([a-f0-9]+)", text)
    return m.group(1) if m else None


def flash_device_api(ip, firmware_path, username="root", password="",
                     keep_settings=False, status_cb=None):
    """
    Flash firmware lên thiết bị OpenWrt qua LuCI HTTP.

    Args:
        ip            : địa chỉ IP thiết bị
        firmware_path : đường dẫn file .bin trên máy tính
        username      : LuCI username (mặc định "root")
        password      : LuCI password (mặc định rỗng — Barrier Breaker không có pass)
        keep_settings : True = giữ cấu hình cũ sau flash
        status_cb     : callback(str) cập nhật tiến độ lên UI

    Returns:
        "DONE"     — flash thành công
        "FAIL: …"  — thất bại, kèm lý do
    """
    base_url  = f"http://{ip}"
    login_url = f"{base_url}/cgi-bin/luci"
    session   = requests.Session()

    try:
        # ── STEP 1: Login ────────────────────────────────────────────
        if status_cb:
            status_cb("Logging in...")

        # Phát hiện field name tương thích Barrier Breaker vs OpenWrt mới
        try:
            page_html = session.get(login_url, timeout=10).text
        except Exception:
            page_html = ""

        if 'name="luci_username"' in page_html:
            login_data = {"luci_username": username, "luci_password": password}
        else:
            login_data = {"username": username, "password": password}

        resp = session.post(login_url, data=login_data,
                            timeout=10, allow_redirects=True)

        if resp.status_code == 403:
            return "FAIL: Login denied (403)"

        # Lấy stok từ URL → body → redirect history
        stok = (_extract_stok(resp.url)
                or _extract_stok(resp.text)
                or next(
                    (_extract_stok(h.headers.get("Location", ""))
                     for h in resp.history
                     if _extract_stok(h.headers.get("Location", ""))),
                    None
                ))

        if not stok and "sysauth" not in str(session.cookies):
            return "FAIL: Login failed — no session"

        flash_url = (
            f"{base_url}/cgi-bin/luci/;stok={stok}/admin/system/flashops"
            if stok else
            f"{base_url}/cgi-bin/luci/admin/system/flashops"
        )

        # ── STEP 2: Upload Firmware ──────────────────────────────────
        if status_cb:
            status_cb("Uploading firmware...")

        filename = os.path.basename(firmware_path)
        extra    = {"keep": "on"} if keep_settings else {}

        with open(firmware_path, "rb") as f:
            resp = session.post(
                flash_url,
                data=extra,
                files={"image": (filename, f, "application/octet-stream")},
                timeout=300,
            )

        if resp.status_code != 200:
            return f"FAIL: Upload HTTP {resp.status_code}"

        body = resp.text.lower()
        if "invalid image" in body or "bad image" in body:
            return "FAIL: Invalid firmware image"
        if "unsupported" in body or "not compatible" in body:
            return "FAIL: Firmware not compatible"
        if "verify" not in body or "proceed" not in body:
            return ("FAIL: Upload ignored by server"
                    if 'name="image"' in resp.text
                    else "FAIL: Unexpected response after upload")

        # ── STEP 3: Confirm (Proceed) ────────────────────────────────
        if status_cb:
            status_cb("Confirming (Proceed)...")

        confirm = {"step": "2", "keep": "on" if keep_settings else ""}
        try:
            session.post(flash_url, data=confirm, timeout=300)
        except (requests.exceptions.ConnectionError,
                requests.exceptions.ReadTimeout):
            pass  # Đứt kết nối khi reboot = bình thường

        if status_cb:
            status_cb("Rebooting...")
        time.sleep(3)
        return "DONE"

    except requests.ConnectionError:
        return "FAIL: Cannot connect"
    except requests.Timeout:
        return "DONE (rebooting)"
    except Exception as e:
        return f"FAIL: {e}"
    finally:
        session.close()